Gen. Jack Keane, former vice chief of staff of the U.S. Army, called the United States' 16-year-long involvement in Afghanistan a "disgrace" and said some 10,000 to 20,000 additional troops were needed to win the war.

Keane spoke with Fox News on Friday as reports surfaced the Pentagon will send roughly 4,000 additional American forces to fight a reinvigorated Taliban insurgency in Afghanistan.

Defense Secretary Jim Mattis has not made an announcement on increasing troop levels in Afghanistan, but a Trump administration official told the Associated Press such an announcement could come as early as next week.

Keane said the 4,000 figure is "only speculation at this point" and not enough to defeat the Taliban and boost the Afghan Army's military might. (...)